// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/logging_win.h"
#include "base/memory/singleton.h"
#include <initguid.h> // NOLINT
#include <windows.h>

#define TRACE_LEVEL_NONE        0   // Tracing is not on
#define TRACE_LEVEL_CRITICAL    1   // Abnormal exit or termination
#define TRACE_LEVEL_FATAL       1   // Deprecated name for Abnormal exit or termination
#define TRACE_LEVEL_ERROR       2   // Severe errors that need logging
#define TRACE_LEVEL_WARNING     3   // Warnings such as allocation failure
#define TRACE_LEVEL_INFORMATION 4   // Includes non-error cases(e.g.,Entry-Exit)
#define TRACE_LEVEL_VERBOSE     5   // Detailed traces from intermediate steps
#define TRACE_LEVEL_RESERVED6   6
#define TRACE_LEVEL_RESERVED7   7
#define TRACE_LEVEL_RESERVED8   8
#define TRACE_LEVEL_RESERVED9   9

namespace logging {

using base::win::EtwEventLevel;
using base::win::EtwMofEvent;

DEFINE_GUID(kLogEventId,
    0x7fe69228, 0x633e, 0x4f06, 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7);

LogEventProvider::LogEventProvider()
    : old_log_level_(LOG_NONE)
{
}

LogEventProvider* LogEventProvider::GetInstance()
{
    return base::Singleton<LogEventProvider, base::StaticMemorySingletonTraits<LogEventProvider>>::get();
}

bool LogEventProvider::LogMessage(logging::LogSeverity severity,
    const char* file, int line, size_t message_start,
    const std::string& message)
{
    EtwEventLevel level = TRACE_LEVEL_NONE;

    // Convert the log severity to the most appropriate ETW trace level.
    if (severity >= 0) {
        switch (severity) {
        case LOG_INFO:
            level = TRACE_LEVEL_INFORMATION;
            break;
        case LOG_WARNING:
            level = TRACE_LEVEL_WARNING;
            break;
        case LOG_ERROR:
            level = TRACE_LEVEL_ERROR;
            break;
        case LOG_FATAL:
            level = TRACE_LEVEL_FATAL;
            break;
        }
    } else { // severity < 0 is VLOG verbosity levels.
        level = static_cast<EtwEventLevel>(TRACE_LEVEL_INFORMATION - severity);
    }

    // Bail if we're not logging, not at that level,
    // or if we're post-atexit handling.
    LogEventProvider* provider = LogEventProvider::GetInstance();
    if (provider == NULL || level > provider->enable_level())
        return false;

    // And now log the event.
    if (provider->enable_flags() & ENABLE_LOG_MESSAGE_ONLY) {
        EtwMofEvent<1> event(kLogEventId, LOG_MESSAGE, level);
        event.SetField(0, message.length() + 1 - message_start,
            message.c_str() + message_start);

        provider->Log(event.get());
    } else {
        const size_t kMaxBacktraceDepth = 32;
        void* backtrace[kMaxBacktraceDepth];
        DWORD depth = 0;

        // Capture a stack trace if one is requested.
        // requested per our enable flags.
        if (provider->enable_flags() & ENABLE_STACK_TRACE_CAPTURE)
            depth = CaptureStackBackTrace(2, kMaxBacktraceDepth, backtrace, NULL);

        EtwMofEvent<5> event(kLogEventId, LOG_MESSAGE_FULL, level);
        if (file == NULL)
            file = "";

        // Add the stack trace.
        event.SetField(0, sizeof(depth), &depth);
        event.SetField(1, sizeof(backtrace[0]) * depth, &backtrace);
        // The line.
        event.SetField(2, sizeof(line), &line);
        // The file.
        event.SetField(3, strlen(file) + 1, file);
        // And finally the message.
        event.SetField(4, message.length() + 1 - message_start,
            message.c_str() + message_start);

        provider->Log(event.get());
    }

    // Don't increase verbosity in other log destinations.
    if (severity < provider->old_log_level_)
        return true;

    return false;
}

void LogEventProvider::Initialize(const GUID& provider_name)
{
    LogEventProvider* provider = LogEventProvider::GetInstance();

    provider->set_provider_name(provider_name);
    provider->Register();

    // Register our message handler with logging.
    SetLogMessageHandler(LogMessage);
}

void LogEventProvider::Uninitialize()
{
    LogEventProvider::GetInstance()->Unregister();
}

void LogEventProvider::OnEventsEnabled()
{
    // Grab the old log level so we can restore it later.
    old_log_level_ = GetMinLogLevel();

    // Convert the new trace level to a logging severity
    // and enable logging at that level.
    EtwEventLevel level = enable_level();
    if (level == TRACE_LEVEL_NONE || level == TRACE_LEVEL_FATAL) {
        SetMinLogLevel(LOG_FATAL);
    } else if (level == TRACE_LEVEL_ERROR) {
        SetMinLogLevel(LOG_ERROR);
    } else if (level == TRACE_LEVEL_WARNING) {
        SetMinLogLevel(LOG_WARNING);
    } else if (level == TRACE_LEVEL_INFORMATION) {
        SetMinLogLevel(LOG_INFO);
    } else if (level >= TRACE_LEVEL_VERBOSE) {
        // Above INFO, we enable verbose levels with negative severities.
        SetMinLogLevel(TRACE_LEVEL_INFORMATION - level);
    }
}

void LogEventProvider::OnEventsDisabled()
{
    // Restore the old log level.
    SetMinLogLevel(old_log_level_);
}

} // namespace logging
